Telephones have already been established as a convenient means for communication with a person at a remote location in daily life. Many situations are present in which one wishes to share information with a person with whom a conversation is being held by telephone. For example, one may wish to share a computer screen in front of him/her with a called person to make arrangements during a telephone call.
In a current telephone system (including cellular phones), however, no associated function with a device near a user is provided. Thus, the following complicated operations need to be performed in order to share information with a person to whom a telephone call is being made.                (1) To ask a telephone partner a network address of a device in front of the partner.        (2) The partner answers it over the telephone (verbally in conversation).        (3) To tell the telephone partner a network address of a device in front of him/her verbally in conversation.        (4) To activate a screen sharing application (for example “a sharing blackboard” on each device to input the address of the partner.        
In addition, the following information handling is also needed verbally in conversation or through manual operations when one wishes to transfer a file to a person to whom a telephone call is being made.
(1) To ask the telephone partner an address (a mail address or an address to which the file is to be transferred) and let the partner tell it verbally in conversation
(2) Input the address manually to a device in front of him/her to transfer the file.
In these operations, since only the addresses of the partners are exchanged through a secured telephone network, transmitted information cannot be protected from an external third party.. When confidentiality of communication is ensured, a key for encryption also needs to be shared with the telephone partner, and performing this by verbal information exchange and manual input is very complicated.
On the other hand, a technique for providing a telephone function through the Internet network has become common like so-called “IP telephone,” so that it is expected that a telephone set can transmit and receive an IP packet.